Limits provide simple load management by limiting the number of tasks submitted by a specific ecflow_server.

suite test
 limit l1 2
 family f5
     inlimit l1
     task t1
     task t2
     task t3
     .....
 endfamily
endsuite

In the 5 series, this has been extended to Family's.

When a family is limited, the child tasks are unconstrained. In this case, only two families can run at a time. All the tasks in the family can start at once

suite test
 limit fam 2 
 family f1
     inlimit -n fam
     task t1
     task t2
 endfamily
 family f2
     inlimit -n fam
     task t1
     task t2
 endfamily
 family f3
     inlimit -n fam
     task t1
     task t2
 endfamily
endsuite

In this case, we want family limits, but also want to constrain the tasks, such that one task in the active family can run.

suite test
 limit fam 1 
 limit T
 inlimit T
 family f1
     inlimit -n fam
     task t1
     task t2
 endfamily
 family f2
     inlimit -n fam
     task t1
     task t2
 endfamily
 family f3
     inlimit -n fam
     task t1
     task t2
 endfamily
endsuite